<title>[POI1999] 三色二叉树</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span> <span class="pl-cpf">&lt;iostream&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span> <span class="pl-cpf">&lt;string&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
<span class="pl-k">const</span> <span class="pl-kt">int</span> <span class="pl-n">maxn</span> <span class="pl-o">=</span> <span class="pl-mi">10005</span><span class="pl-p">;</span>
<span class="pl-n">string</span> <span class="pl-n">s</span><span class="pl-p">;</span>
<span class="pl-kt">int</span> <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">maxn</span><span class="pl-p">][</span><span class="pl-mi">3</span><span class="pl-p">],</span> <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">maxn</span><span class="pl-p">][</span><span class="pl-mi">3</span><span class="pl-p">],</span><span class="pl-n">n</span><span class="pl-p">;</span>
<span class="pl-kt">int</span> <span class="pl-nf">dfs</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">root</span><span class="pl-p">)</span> <span class="pl-p">{</span>
    <span class="pl-k">if</span> <span class="pl-p">(</span><span class="pl-n">s</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">]</span> <span class="pl-o">==</span> <span class="pl-sc">&#39;0&#39;</span><span class="pl-p">)</span> <span class="pl-p">{</span>
        <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-mi">1</span><span class="pl-p">;</span>
        <span class="pl-k">return</span> <span class="pl-n">root</span><span class="pl-p">;</span>
    <span class="pl-p">}</span>
    <span class="pl-kt">int</span> <span class="pl-n">lend</span> <span class="pl-o">=</span> <span class="pl-n">dfs</span><span class="pl-p">(</span><span class="pl-n">root</span> <span class="pl-o">+</span> <span class="pl-mi">1</span><span class="pl-p">);</span><span class="pl-c1">//未必是左子树</span>
    <span class="pl-k">if</span> <span class="pl-p">(</span><span class="pl-n">s</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">]</span> <span class="pl-o">==</span> <span class="pl-sc">&#39;1&#39;</span><span class="pl-p">)</span> <span class="pl-p">{</span>
        <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">],</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">])</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">;</span>
        <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]);</span>
        <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]);</span>
        <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">],</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">])</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">;</span>
        <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]);</span>
        <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]);</span>
        <span class="pl-k">return</span> <span class="pl-n">lend</span><span class="pl-p">;</span>
    <span class="pl-p">}</span> <span class="pl-k">else</span> <span class="pl-p">{</span>
        <span class="pl-kt">int</span> <span class="pl-n">rend</span> <span class="pl-o">=</span> <span class="pl-n">dfs</span><span class="pl-p">(</span><span class="pl-n">lend</span> <span class="pl-o">+</span> <span class="pl-mi">1</span><span class="pl-p">);</span>
        <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">],</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">])</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">;</span>
        <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">],</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]);</span>
        <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">],</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]);</span>
        <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">],</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">])</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">;</span>
        <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">],</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]);</span>
        <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">],</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-n">lend</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]);</span>
        <span class="pl-k">return</span> <span class="pl-n">rend</span><span class="pl-p">;</span>
    <span class="pl-p">}</span>
<span class="pl-p">}</span>
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">()</span> <span class="pl-p">{</span>
    <span class="pl-n">cin</span> <span class="pl-o">&gt;&gt;</span> <span class="pl-n">s</span><span class="pl-p">;</span>
    <span class="pl-n">n</span><span class="pl-o">=</span><span class="pl-n">s</span><span class="pl-p">.</span><span class="pl-n">size</span><span class="pl-p">();</span>
    <span class="pl-n">dfs</span><span class="pl-p">(</span><span class="pl-mi">0</span><span class="pl-p">);</span>
    <span class="pl-n">cout</span><span class="pl-o">&lt;&lt;</span><span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-mi">0</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span> <span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-mi">0</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">],</span> <span class="pl-n">maxv</span><span class="pl-p">[</span><span class="pl-mi">0</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]))</span><span class="pl-o">&lt;&lt;</span><span class="pl-s">&quot; &quot;</span><span class="pl-o">&lt;&lt;</span><span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-mi">0</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-mi">0</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">],</span> <span class="pl-n">minv</span><span class="pl-p">[</span><span class="pl-mi">0</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]))</span><span class="pl-o">&lt;&lt;</span><span class="pl-n">endl</span><span class="pl-p">;</span>
    <span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
</cpde></pre></div>